SQL: Selecting Expressions

• We can SELECT many kinds of expressions: columns, like we've seen already; but also constants, mathematical expressions, and function calls. For example, if we SELECT 1, we get 1 back. If we SELECT 1 + 1, we get 2 back.

• >

  exec(`SELECT 1`);

  Result:

  Run Code

• >

  exec(`SELECT 1 + 1`);

  Result:

  Run Code

• The output here is the same as ever: an array of objects. But now, there are no column names. Instead, the properties on the "row" object are the expressions that we queried.

• >

  exec(`SELECT 2 * 3`);

  Result:

  [{'2 * 3': 6}]

• We can also query functions that return values dynamically. For example, the current date is written as DATE('now') in SQLite. This query asks: is the current date after DATE(0), which was January 1, 1970?

• >

  exec(`SELECT DATE('now') > DATE(0)`);

  Result:

  Run Code

• Here's a code problem:

  Select the number 17.

  9

  1

  exec(`

  10

  2

  SELECT 17

  11

  3

  `);

  Goal:

  [{'17': 17}]

  Yours:

  [{'17': 17}]

  Show Author's Answer